Age-related changes in renal function, membrane metabolism, transporter activity and abundance in hypokalemic Fischer 344 x Brown-Norway F1 rats
type: CreativeWork
description: Potassium depletion (-K) is a common electrolyte abnormality in elderly humans, occurring as a consequence of diuretic use or poor oral intake. The efifects of diet-induced hypokalemia on renal function, cortical brush-border (BBM) and basolateral membrane (BLM) protein and lipid metabolism, transporter activity and abundance were examined in non-obese male Fischer 344 x Brown-Norway Fl rats of 4 mo and 30 mo of age. These experiments were designed to examine whether age-associated changes occur in these parameters and whether the aged animals respond differently to potassium depletion as compared tq the young animals. Western blot analysis of the al-subunit Na,K-ATPase and sodium hydrogen exchanger-1 (NHE-1) in BLM as well as NHE-3 in BBM was determined. Adenosine triphosphatase (ATPase) activity was measured in membrane vesicles and three microdissected segments of the nephron (proximal convoluted tubule [PCT], cortical collecting tubule [CCT], and medullary collecting tubule [MCT]). In both age groups, potassium depletion decreased total body potassium content; plasma ldosterone fell while plasma cholesterol and muscle Na concentration increased. Hypokalemia caused a urinary concentrating defect in addition to a rise in urinary excretion of ammonium, titratable acid and phosphate. Blood urea nitrogen, plasma bicarbonate, and glucose increased significantly with -K, but only in the senescent rats. Fractional excretion of Na and CI also increased, but only in the young hypokalemic animals. The control aged rats had a 35% lower plasma aldosterone and a 42% higher plasma cholesterol as compared to their control young counterparts. Protein and phospholipid concentration and biosynthesis of BBM and BLM were measured after U-^14 C-leucine and 32^P incorporation (24 hr), respectively. In the young animals, hypokalemia increased protein concentration in both membranes, but BLM biosynthesis fell. In the senescent group, hypokalemia did not change protein concentration, how…
abstract: Potassium depletion (-K) is a common electrolyte abnormality in elderly humans, occurring as a consequence of diuretic use or poor oral intake. The efifects of diet-induced hypokalemia on renal function, cortical brush-border (BBM) and basolateral membrane (BLM) protein and lipid metabolism, transporter activity and abundance were examined in non-obese male Fischer 344 x Brown-Norway Fl rats of 4 mo and 30 mo of age. These experiments were designed to examine whether age-associated changes occur in these parameters and whether the aged animals respond differently to potassium depletion as compared tq the young animals. Western blot analysis of the al-subunit Na,K-ATPase and sodium hydrogen exchanger-1 (NHE-1) in BLM as well as NHE-3 in BBM was determined. Adenosine triphosphatase (ATPase) activity was measured in membrane vesicles and three microdissected segments of the nephron (proximal convoluted tubule [PCT], cortical collecting tubule [CCT], and medullary collecting tubule [MCT]). In both age groups, potassium depletion decreased total body potassium content; plasma ldosterone fell while plasma cholesterol and muscle Na concentration increased. Hypokalemia caused a urinary concentrating defect in addition to a rise in urinary excretion of ammonium, titratable acid and phosphate. Blood urea nitrogen, plasma bicarbonate, and glucose increased significantly with -K, but only in the senescent rats. Fractional excretion of Na and CI also increased, but only in the young hypokalemic animals. The control aged rats had a 35% lower plasma aldosterone and a 42% higher plasma cholesterol as compared to their control young counterparts. Protein and phospholipid concentration and biosynthesis of BBM and BLM were measured after U-^14 C-leucine and 32^P incorporation (24 hr), respectively. In the young animals, hypokalemia increased protein concentration in both membranes, but BLM biosynthesis fell. In the senescent group, hypokalemia did not change protein concentration, how…
author: Eiam-Ong, Somchit
language: eng
keywords: Proteinuria, Hypokalemia, Renal tubular transport, Potassium, Kidneys, Potassium deficiency diseases
date published: 1998-05
date modified: 2026-07-24T05:04:54Z
provider: Texas Technology University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Texas Tech University

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2346/11433